Polyamide-containing copolymers comprise a diverse group of copolymers. Typically, a polyamide-containing copolymer comprises repeat units that have at least two segments; a polyamide segment having a high thermal transition temperature, which is often referred to as a hard segment, and a polymeric segment having a low thermal transition temperature, which is chemically bonded to the hard segment and is often referred to as a soft segment. Typical examples of soft segments are certain polyesters, polyethers, polyolefins, polyols, polyetheresters, and mixtures thereof. Polyesteramides, polyetheramides and polyetheresteramides are examples of polyamide-containing copolymers.
Some members of polyamide-containing copolymers have utility in formation of fibers and films. Other members of polyamide-containing copolymers comprise thermoplastic elastomers and are melt processible to make molded articles, for example, seals, gaskets, and bushings. For a particular primary application, desirable physical properties of a polyamide-containing copolymer have been sought by making the copolymer to have certain hard segments and soft segments using monomers having specific structures. For example, U.S. Pat. No. 4,129,715 generally relates to certain polyetheramides and polyesteramides with crystalline polyamide hard-segments useful for producing articles by injection-molding processes at temperatures below about 285° C.
Polymer melt processing, such as injection or compression molding, film extrusion or blown-film extrusion, fiber spinning, sheet casting, tube extrusion, and the like, comprises heating a solid polymer feed to a flow temperature to create a highly processible polymer melt. For a particular polymer, a flow temperature is generally greater than the melting temperature (Tm) for a semi-crystalline polymer or the glass transition temperature (Tg) for an amorphous polymer. A flow temperature of a particular polymer is also limited to be below a temperature at which thermal degradation of the polymer begins. There is a need for a melt processible polyamide-containing copolymer that has thermal transitions (Tm or Tg) below about 200° C. One of the benefits derived from melt processing a polyamide-containing copolymer at a lower temperature is minimizing or preventing degradation of the copolymer.